NECTAR SOURCES FOR LARGE-WINGED BUTTERFLIES OF THE MID-ATLANTIC

Ooooo, a monarch! It takes an erratic path across the garden, bright orange wings gliding and flapping, drifting and fluttering. It floats down and lights on a stalk of common milkweed and after a momentary pause, the dark abdomen curls and a single egg is precisely laid underneath a small, tender leaf. She repeats the process twice more. The mother butterfly discovers another stand of young shoots on the opposite side of the garden and continues her delicate dance. An egg here. Flutter flutter. Another egg gently placed there.

Three years have quickly passed since I planted tiny milkweed plants and they now command ample portions of this wildlife habitat, creating a welcoming haven for monarchs—adults and larvae alike. It’s mid-summer, with clear skies and still air; the perfect conditions for butterfly spying.

Scrutinizing the plants that make up this front yard garden, I stand in the warming sun and consider whether there’ll be sufficient nectar for any new monarchs when nearly a month from now the miraculous four stage metamorphosis, from egg to larva to pupa to butterfly, is complete.

The smaller butterflies such as skippers and fritillaries frequent a wide variety of flowers but the large-winged beauties, I’ve noticed, are slightly more discerning. What flowers do they want? This question sent me on the most colorful of journeys …

Are you gonna eat that?

Butterflies are the magical creatures gracefully flitting through princess tales and are undeniably the most beloved of all our insects. Although not the most efficient pollinators when compared to native bees and flies, butterflies nonetheless play an important ecological role.

Most butterflies live on nectar from flowers and some also receive nourishment from pollen, tree sap, rotting fruit, carrion, dung, aphid honeydew and minerals found in wet sand or dirt. They have a proboscis, a long complex food canal that is straw-like and coiled when not in use. Proboscises come in different lengths and can dictate which flower a butterfly may drink from.

What else might make one flower more alluring to a particular butterfly than the next? Scent and color can be enticing components. Some researchers also identified butterfly morphology as a factor; they found that species with a “high wing load” generally preferred clustered or nectar-rich flowers. This would explain all the swallowtails on Joe Pye Weed!

You may be tempted to plant butterfly bush (Buddleja spp.and cultivars) because you notice your neighbor’s attracts butterflies late in the growing season. Please resist the urge to do so! Butterfly bush is an introduced plant from Asia that does not support local food webs. It’s also an invasive shrub that outcompetes native flora for resources and negatively impacts all our wildlife. Some prudent states have taken steps to ban the sale of butterfly bush.

FROM EGG TO ADULT:Support a butterfly’s full life cycle

A spicebush swallowtail caterpillar lounging on one of its host plants, spicebush (Lindera benzoin).

While wildflower nectar is a necessary habitat component for butterflies, other plant life such as native grasses, vines, shrubs and trees are equally crucial for food and shelter. A landscape with tons of plant diversity will help not only butterflies but also our other wild critters— great and small and every life in between.

Let’s grow butterflies! It’s easy to do: just add the plant that their larvae will eat. These specific plants that caterpillars need for food are called host plants. Monarchs, as we know, require milkweed or Asclepias species to reproduce. Host plants are not optional for caterpillars and some, like those of the zebra swallowtail, the pipevine swallowtail and the monarch, have only one genusof plant that they can eat. What Do Caterpillars Eat by the Washington Area Butterfly Club lists some common butterflies and their typical host plants.

Did you know that butterflies need water, too? You can provide essential moisture and minerals by filling a shallow dish with damp sand or mud. It’s a bit of maintenance but well worth it if you spy even a tiny skipper taking a drink, as I have. And don’t forget to leave the leaf litter! There are butterfly and moth species that overwinter as egg, larva or pupa in the blanket of fallen leaves and debris.Let’s not be tossingout the butterflies we’re trying to encourage.

FLOWER POWER!

Here the spotlight is thrown on a handful of sun-loving native herbaceous plants that large–winged butterflies such as the monarch and swallowtails have been observed to frequent. The bloom times are varied, beginning in early summer and ending in fall, when late-season nectar is crucial for migrating butterflies.

These lovely plants will naturally support smaller butterflies, native bees and insects, as well as other animals throughout the food web. If the plant is a known Lepidoptera (butterfly and moth) caterpillar host, that information from Doug Tallamy’s research is included as well. Remember to choose native plant species that occur naturally in your area to keep wild areas functioning. Happy butterfly watching!

I do not include plant hardiness zone information because if you’re planting regionally native plants, as I hope you are, that information is unnecessary.

Common milkweed (Asclepias syriaca) with an eastern tiger swallowtail and a few other friends, including a silver-spotted skipper. Note the huge leaves designed for hungry monarch caterpillars.

Common Milkweed (Asclepias syriaca)Height: 3 – 5 ft, up to 8 ftBloom time: June – AugustSun: FullMoisture: Medium to LowSoil: Medium to fine sandy, clay, well-drained loamy, rocky calcareous; pH moderateNatural habitat: Fields, pastures, roadsidesNotes: The large leaves of this Asclepias species are sought by monarchs looking to lay their eggs. The USDA Forest Service writes: “Common milkweed is Nature’s mega food market for insects. Over 450 insects are known to feed on some portion of the plant.”Some gardeners consider A. syriaca to be a thug because it spreads by rhizomes and can colonize areas including lawn. Any shoots that pop up where they’re not wanted, though, are easy to pull or cut.Milkweeds are host to 12 species of native caterpillars including the monarch butterfly.Other options: Swamp milkweed(Asclepias incarnata) is a moisture-loving species that does not spread by rhizomes.More information: USDA Forest Service Plant of the Week: Asclepias syriaca

Out in the wild: a zebra swallowtail on butterfly weed (Asclepias tuberosa). Zebra swallowtails have only one host plant: paw paw (Asimina triloba).

A monarch on New England aster (Symphyotrichum novae-angliae). Photo by David Marvin/flickr/cc.

New England Aster (Symphyotrichum novae-angliae)Height: 1 – 6 ft and tallerBloom time: August – OctoberSun: Full, PartMoisture: MediumSoil: Adaptable, rich, sand, loam, clayNatural habitat: Moist, open woods, wet meadows, stream banks, alluvial fieldsNotes: New England aster has a long bloom period and is enjoyed by many insects.It can get leggy in a garden setting; some gardeners continually pinch it back before July to control its height, but note that the blooms may open later.New England aster reseeds abundantly! Share with neighbors!Asters are known to host 112 species of native caterpillars.Other options: Aromatic Aster(Symphyotrichum oblongifolium), New York Aster (Symphyotrichum novi-belgii)

Pasture thistle (Cirsium pumilum) on the left and field thistle (Cirsium discolor), a taller-growing species, on the right. C. discolor photo by Lisa Bright/Earth Sangha.

Pasture Thistle (Cirsium pumilum)Height: 1 – 3 ftBloom time: June – AugustSun: FullMoisture: Medium, LowSoil: Poor, clay, well-drainedNatural habitat: Clearings, meadows, fieldsNotes: Pasture thistle is an uncommon garden plant that’s fun to grow regardless of the pokey spines.It’s a shorter species that may be better suited for garden habitats.Bumble bees enjoy the pollen of the large 2-3 inch flower heads.Many of the commonly seen thistles like bull thistle and Canada thistle are introduced and considered invasive.Host to 27 Lepidoptera species.Other options: There are many native thistles; Field Thistle (Circium discolor) is a tall species, shown on the right side of photo.

Shrub bonus!

The following two woody plants are nearly always recommended as excellent sources of butterfly nectar.

A spicebush butterfly on a buttonbush flower sphere (Cephalanthus occidentalis). The spicebush caterpillar requires the leaves of its host plants, spicebush (Lindera benzoin) and sassafras (Sassafras albidum). Photo by John Flannery/flickr/cc.